PROGRESS IN FORMATION OF SINGLE-PULSE BEAMS BY A CHOPPING SYSTEM AT THE JAEA/TIARA FACILITY

The intervals of beam pulses from a cyclotron are generally tens of ns and they are too short for pulse radiolysis experiments which require beam pulses at intervals over 1 μs (single-pulse beam). A chopping system, consisting of two types of high voltage kickers, is used at the JAEA AVF cyclotron to form single-pulse beam. However, we could not provide single-pulse beam stably over 30 min since the magnetic field of the cyclotron gradually decreased and the number of multiturn extraction increased. The magnetic field is stabilized at present by keeping temperature of the cyclotron magnet constant. In addition, a new technique to measure and control an acceleration beam phase has enabled us to reduce the number of multi-turn extraction easier than before. The single-pulse beam of a 320 MeV 12C6+ is successfully provided without retuning of the cyclotron over 4 h, as a result.IMP;Chinese Academy of Science